Spi Z9390SS Roller Contact Point 0.5in Dia 4-48 Dial Indicator

Product Description

The SPI Z9390SS is a roller-style contact point designed for use with dial indicators. It threads directly onto standard dial indicator stems using a 4-48 thread and features a 0.5-inch diameter roller with a 0.5-inch contact point length. The roller contact style allows the indicator to track workpiece surfaces during dynamic or sliding measurements, reducing friction and drag compared to a standard ball or flat-tip point. Constructed from steel, the Z9390SS delivers durability in shop-floor environments. It is installed by machinists, tool-and-die makers, and quality control technicians on manual or machine-mounted dial indicators.

This contact point is suited for dimensional inspection and machine setup work where a rolling contact is required to ride along a moving or fixed surface without marring it. Common applications include checking runout on rotating shafts, verifying flatness on sliding machine members, and gauging part features in fixture setups. The roller design is especially useful where side-load sensitivity matters and a smooth, consistent contact trace is needed across the measurement stroke.

Key Features

• Roller contact style reduces friction and drag during sliding or dynamic measurements
• 4-48 thread fits standard dial indicator contact point stems
• 0.5-inch roller diameter provides stable surface contact
• 0.5-inch contact point length suits typical indicator reach requirements
• Steel construction for durability in production and inspection environments
• Sold as a single piece, compatible with standard dial indicator accessories

Compatibility

Designed for use with dial indicators that accept 4-48 threaded contact points, which is the standard thread used on the majority of AGD-style dial indicators.

Installation Notes

Installation requires threading the Z9390SS onto the contact point stem of a dial indicator by hand or with a small wrench, taking care not to overtighten and damage the stem threads. Ensure the dial indicator is removed from the measuring setup or securely held before swapping contact points. Verify the roller spins freely after installation and that the thread engagement is secure before placing the indicator under load. Contact point swaps should be followed by a zeroing or re-mastering step to confirm measurement accuracy.